Introduction. Initial post-operative implant instability leads to impaired osseointegration, one of the most common reasons for aseptic loosening and revision surgery. In this study, we developed a novel murine model of implant instability and demonstrated the anabolic effect of immediate and delayed intermittent Parathyroid Hormone (iPTH) treatment in the setting of instability-induced osseointegration failure. Methods. 3D-printed titanium implants were inserted in an oversized drill-hole in the tibia of C57Bl/6 mice (n=54). After implantation, the mice were randomly divided in 3 treatment groups (control: PBS-vehicle; iPTH; delayed iPTH). Radiographic analysis was performed to confirm signs of implant loosening. Peri-implant tissue formation was assessed through histology. Osseointegration was assessed through µCT and biomechanical pullout testing. Results. Immediate iPTH treatment reduced radiolucencies and induced a distinct pedestal sign distal to the implant stem (white arrow Fig 1A). The PBS treated mice had fibrous tissue implant encapsulation, whereas new mineralized tissue and no fibrous tissue was observed with immediate iPTH treatment (Fig 1E). Delayed iPTH treatment was also able to exhibit significant peri-implant bone mineralization, osteoblasts, angiogenesis, and a reduction of fibrous tissue (Fig 2A-B). iPTH treatment increased the force required to pull out the implant significantly from 8.41 ± 8.15N in the PBS group to 21.49 ± 10.45N and 23.68 ± 8.99N, in the immediate and delayed iPTH treatment groups, respectively (Fig 2D). PBS vehicle resulted in a bone volume/trabecular volume (BV/TV) of 0.23 ± 0.03, while immediate and delayed iPTH treatment increased BV/TV significantly to 0.46 ± 0.07 and 0.34 ± 0.10, respectively (Fig 2E). Conclusion. Immediate iPTH treatment prevents peri-implant fibrous tissue formation and enhances peri-implant bone formation in our murine model of mechanical instability. Delayed iPTH treatment was able to resolve the peri-implant fibrous tissue and stimulate bone formation. This study potentially addresses a leading cause of aseptic loosening by demonstrating that initial implant instability can be rescued by iPTH even with delayed start of treatment. For any figures or tables, please contact authors directly

Aims

This study aimed to explore the biological and clinical importance of dysregulated key genes in osteoarthritis (OA) patients at the cartilage level to find potential biomarkers and targets for diagnosing and treating OA.

Aims

To evaluate whether low-intensity pulsed ultrasound (LIPUS) accelerates bone healing at osteotomy sites and promotes functional recovery after open-wedge high tibial osteotomy (OWHTO).

Aims

The aim of this study was to determine the long-term risk of undergoing knee arthroplasty in a cohort of patients with meniscal tears who had undergone arthroscopic partial meniscectomy (APM).

We carried out an audit on the result of achieving early walking in total knee replacement after instituting a new rehabilitation protocol, and assessed its influence on the development of deep-vein thrombosis as determined by Doppler ultrasound scanning on the fifth post-operative day. Early mobilisation was defined as beginning to walk less than 24 hours after knee replacement.

Between April 1997 and July 2002, 98 patients underwent a total of 125 total knee replacements. They began walking on the second post-operative day unless there was a medical contraindication. They formed a retrospective control group. A protocol which allowed patients to start walking at less than 24 hours after surgery was instituted in August 2002. Between August 2002 and November 2004, 97 patients underwent a total of 122 total knee replacements. They formed the early mobilisation group, in which data were prospectively gathered. The two groups were of similar age, gender and had similar medical comorbidities. The surgical technique and tourniquet times were similar and the same instrumentation was used in nearly all cases. All the patients received low-molecular-weight heparin thromboprophylaxis and wore compression stockings post-operatively.

In the early mobilisation group 90 patients (92.8%) began walking successfully within 24 hours of their operation. The incidence of deep-vein thrombosis fell from 27.6% in the control group to 1.0% in the early mobilisation group (chi-squared test, p < 0.001). There was a difference in the incidence of risk factors for deep-vein thrombosis between the two groups. However, multiple logistic regression analysis showed that the institution of an early mobilisation protocol resulted in a 30-fold reduction in the risk of post-operative deep-vein thrombosis when we adjusted for other risk factors.

Objective

Mortality rates reported by the National Joint Registry for England and Wales (NJR) were higher following cemented total knee replacement (TKR) compared with uncemented procedures. The aim of this study is to examine and compare the effects of cemented and uncemented TKR on the activation of selected markers of inflammation, endothelium, and coagulation, and on the activation of selected cytokines involved in the various aspects of the systemic response following surgery.

Pulmonary embolism is a serious complication after arthroscopy of the knee, about which there is limited information. We have identified the incidence and risk factors for symptomatic pulmonary embolism after arthroscopic procedures on outpatients. The New York State Department of Health Statewide Planning and Research Cooperative System database was used to review arthroscopic procedures of the knee performed on outpatients between 1997 and 2006, and identify those admitted within 90 days of surgery with an associated diagnosis of pulmonary embolism. Potential risk factors included age, gender, complexity of surgery, operating time defined as the total time that the patient was actually in the operating room, history of cancer, comorbidities, and the type of anaesthesia. We identified 374 033 patients who underwent 418 323 outpatient arthroscopies of the knee. There were 117 events of pulmonary embolism (2.8 cases for every 10 000 arthroscopies). Logistic regression analysis showed that age and operating time had significant dose-response increases in risk (p < 0.001) for a subsequent admission with a pulmonary embolism. Female gender was associated with a 1.5-fold increase in risk (p = 0.03), and a history of cancer with a threefold increase (p = 0.05).

These risk factors can be used when obtaining informed consent before surgery, to elevate the level of clinical suspicion of pulmonary embolism in patients at risk, and to establish a rationale for prospective studies to test the clinical benefit of thromboprophylaxis in high-risk patients.